Review of the Prior Art
Many attempts have been made in the prior art to provide a mechanically operated toothbrush for personal use, most being electrically driven. In U.S. Pat. No. 2,598,275, Lakim discloses an electrically actuated oscillatory toothbrush having a reciprocable shaft driven by an oscillatory or vibratory motor. In U.S. Pat. No. 2,655,674, for example, Grover provides a lip guard and a pair of rotary brushes for cleaning both sides of a row of teeth simultaneously. In my prior U.S. Pat. No. 3,702,487, there is described a mechanical toothbrush having a crank-shaped drive shaft that maintains the bristles disposed at all times toward selected teeth. The present invention provides an alternative means of accomplishing the objectives of my prior patent.
These and other prior art attempts have shown keen awareness of the problems which a toothbrush user commonly encounters in brushing the multi-surfaced teeth and gums without tending to move the gums away from the necks of the teeth or to force food particles therebetween. However, except for my prior patent no known prior art device has effectively solved these problems and provided a mechanically operated toothbrush which cleans the sides of teeth, the cuspidate surfaces thereof, and the interdental areas while selectively able to massage gums as dexterously, efficiently, and sensitively as a hand-operated toothbrush is commonly able to do.
The apparent difficulty is that the sweeping motion generally used in hand operaton of a toothbrush is not effectively simulated by the rotary or reciprocatory motion of the prior art devices. Another difficulty of prior art devices is generally caused by unwanted contact of bristles of rotary toothbrushes with the cheek or gums. The device of the present invention has been found to be as efficient as the hand brushing method.